package algorithm;

public class leetcode_0123 {
    public int maxProfit(int[] prices) {
        int len=prices.length;
        int[][] dp=new int[len][4];
        dp[0][0]=-1*prices[0];
        dp[0][1]=0;
        dp[0][2]=-1*prices[0];
        dp[0][3]=0;
        for(int i=1;i<len;++i){
            dp[i][0]=max(dp[i-1][0],-1*prices[i]);
            dp[i][1]=max(dp[i-1][1],dp[i-1][0]+prices[i]);
            dp[i][2]=max(dp[i-1][2],dp[i-1][1]-prices[i]);
            dp[i][3]=max(dp[i-1][3],dp[i-1][2]+prices[i]);
        }
        return max(dp[len-1][1],dp[len-1][3]);
    }
    public int max(int a,int b){
        return (a<b)?b:a;
    }
}
